What technical points should be noted when growing alfalfa for seed?

Many people are not very familiar with alfalfa and wonder what it is. In fact, it is a fairly common clover, and it is widely planted in our country, mainly used for lawn establishment and environmental landscaping, and it can also be used as feed for livestock, so its uses are still very wide-ranging.

What is alfalfa

Alfalfa is the general name for plants of the genus Medicago, commonly known as “clover” (clover can also refer to other plants of the tribe Trifolieae). It is a perennial flowering plant. The most famous among them is alfalfa (Medicago sativa), which is used as forage. It is livestock feed. Alfalfa is known as the “king of forage grasses”; it not only has high yield, but also has excellent grass quality, and all kinds of livestock and poultry like to eat it. At present, the planting area of alfalfa in our country is about 1.33 million hm^2. With the development of the commodity economy, the scale of alfalfa industrialization has developed rapidly in recent years, and the planting area of alfalfa is expanding.

The main values of alfalfa

Alfalfa has 4 special values:

1. In spring, when the stems and leaves are about 30 cm, it is a superior vegetable and can be considered a typical green food. It sells well year after year in vegetable markets everywhere and is popular every year. Eating it often makes people feel relaxed and comfortable and light all over.

2. The whole plant is used as medicine. It is cut once each year in May-June, and afterward cut once every one and a half months or 2 months, then dried in the sun for later use.

3. It is also a good forage grass. Its whole plant is 50 cm to 90 cm tall. Cattle, horses, sheep, pigs, and chickens all like to eat it, and it grows fast, does not need feed, and does not get sick, while the coat and appearance are smooth and shiny. After being cut in late autumn and dried in the sun, it is an excellent forage grass for livestock to overwinter on, with a yield of 1500-2000 kg per mu.

4. Alfalfa is also a very good green barrier. It has tenacious vitality and is an excellent variety for preventing wind and fixing sand and for greening mountainous areas and barren zones. Every year it is lush and green, adding an infinitely beautiful scenic spot to nature.

Key points to note in alfalfa seed production

1. Choose the land, prepare the land, and sow with sufficient soil moisture. Choose a flat and relatively fertile plot as the seed field. Because alfalfa seeds are small and have poor ability to push through the soil, the land must be finely prepared before sowing, and sufficient soil moisture must be ensured for sowing. The sowing method can be drilling or broadcasting. The sowing depth is preferably 2 cm. 2. Apply sufficient base fertilizer. Alfalfa is perennial, and apart from seed production, it can also be harvested 2 times a year. Therefore, a sufficient nutrient supply is needed. Before land preparation, sufficient base fertilizer should be applied; generally, 2000-3000 kg of organic fertilizer and 50-100 kg of superphosphate are applied per mu. When it enters the flowering stage, it should be watered in time, and 10 kg of urea and 0.5 kg of boron fertilizer should be applied with the water. 3. Control field density well. After 1-2 years of growth, alfalfa becomes very dense, and ventilation and light penetration in the middle and lower parts are very poor, which is not conducive to pollination and seed maturation. In spring, when alfalfa turns green, depending on the density, use an iron rake to rake 2-3 times to remove some plants and tillers and improve ventilation and light penetration. Generally, this can increase yield by more than 30%.

4. Artificial supplementary pollination. Alfalfa is a cross-pollinated crop and needs insects to pollinate it. During the flowering period, ventilation can be provided to help alfalfa pollinate and increase the seed-setting rate. 5. Harvest in time. Alfalfa has a relatively long flowering period, and the seeds mature unevenly. Harvesting too late will cause the lower seeds to fall off, so it should be harvested in time when the middle and lower pods turn brown. 6. Do a good job of seed treatment. Newly harvested seeds of the current year have a dormancy period of 1-2 months, but the seed harvest period is generally in late July, which is also the sowing season. If seeds are urgently needed for sowing, the dormancy can be broken by freezing at a low temperature below -5 to -10 degrees C for 48 hours, then exposing them to the sun for 12 hours, and finally rolling them with a light automobile. After the above treatment, the grape germination rate can reach 75-80%.

Alfalfa sowing methods  

1. Seed treatment. The seeds should be cleaned and dried in the sun so that the seed purity reaches 90%; before sowing, pesticides, herbicides, rhizobia, and fertilizers can be mixed in proportion for seed dressing to avoid seedling-stage pests and diseases. Dressing seeds with bacterial fertilizers such as rhizobia (1 kg of rhizobia can dress 10 kg of seeds) can increase yield by more than 20%.  

2. Sowing time. Seed germination requires two conditions: first, the soil temperature is 5 degrees C--6 degrees C, and the optimum temperature is within 25 degrees C; second, more water is needed. Spring sowing and autumn sowing give the best results. Plots that are somewhat saline-alkaline are not suitable for spring sowing, as this easily causes seedling death.  

(1) Spring sowing. In spring, sowing should be done before Qingming (late March--early April). At this time, soil moisture is high, and it is easy to obtain a full stand. If too late, it coincides with spring drought, and emergence is difficult.  

(2) Summer sowing. Generally in June--July. During this period, temperatures are high, there is more rain, and seedlings grow quickly, but there are also many weeds, and pests and diseases occur frequently.  

(3) Autumn sowing. Generally in late August--early September. During this period, after the rainy season, soil moisture is good, the temperature is suitable, weed growth slows down, and the sowing success rate is the highest. Regardless of which sowing method is used, it should be combined with rain or irrigation, and after rain is best. After sowing, the soil should be pressed to help the seeds germinate.  

3. Sowing method. Drilling is generally used, with a row spacing of 30 cm--40 cm. The currently promoted dense-ridge sparse-planting technique uses a row spacing of 15 cm--20 cm, which not only increases coverage and raises yield, but also facilitates field management.  

4. Sowing rate. For imported seeds, the amount used per mu is 0.75 kg--1.0 kg; for domestic seeds, the amount used per mu is 1.0 kg--1.5 kg. The amount used in saline-alkaline land should be appropriately increased. In arid areas, because of insufficient water, sowing should not be too dense. When dry, use the lower limit per mu; when moist, use the upper limit.  

5. Sowing depth. Alfalfa seeds are very small, and the sowing depth depends on the soil type: sow shallowly in wet soil and slightly deeper in dry soil. Generally 2 cm--3 cm, 3 cm--4 cm for sandy soil, and 2 cm for clay.  

6. Pressing. If the soil is loose, press it once before sowing to make it easier to control the depth; press it once again after sowing, which helps preserve soil moisture.

It can thus be seen that alfalfa can not only beautify the environment and has great ornamental value, but after drying it can also be used as medicinal material and can also play a certain role in regulating some human diseases. Therefore, everyone should not underestimate this small clover; in fact, it can release great effects.